Develop Reference

How to create database if not exist in c# Winforms

I want to create a database if it does not exist. I am trying to do it with this code but it has errors and I get this message
enter image description here
Please help.
Code:
if(dbex == false)
{
string str;
SqlConnection mycon = new SqlConnection("Server=.\\sqlexpress;initial catalog=Masalehforoshi;Integrated security=SSPI;database=master");
str = "CREATE DATABASE [Masalehforoshi] CONTAINMENT = NONE ON PRIMARY" +
"(NAME=N'Masalehforoshi'," +
#"FILENAME=N'C:\data\Masalehforoshi.mdf' " +
",SIZE=3072KB,MAXSIZE=UNLIMITED,FILEGROWTH=1024KB)" +
"LOG ON (NAME=N'Masalehforoshi_log.', " +
#"FILENAME=N'C:\Masalehforoshi_log.ldf' "+
",SIZE=1024KB,MAXSIZE=2048GB,FILEGROWTH=10%)";
SqlCommand mycommand = new SqlCommand(str, mycon);
try
{
mycommand.Connection.Open();
mycommand.ExecuteNonQuery();
}
catch(Exception ex)
{
MessageBox.Show(ex.ToString(), "myprogram", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
finally
{
if(mycon.State == ConnectionState.Open)
{
mycon.Close();
}
}
}

My Create Database function
public bool CreateDatabase(SqlConnection connection, string txtDatabase)
{
String CreateDatabase;
string appPath = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
GrantAccess(appPath); //Need to assign the permission for current application to allow create database on server (if you are in domain).
bool IsExits = CheckDatabaseExists(connection, txtDatabase); //Check database exists in sql server.
if (!IsExits)
{
CreateDatabase = "CREATE DATABASE " + txtDatabase + " ; ";
SqlCommand command = new SqlCommand(CreateDatabase, connection);
try
{
connection.Open();
command.ExecuteNonQuery();
}
catch (System.Exception ex)
{
MessageBox.Show("Please Check Server and Database name.Server and Database name are incorrect .", Text, MessageBoxButtons.OK, MessageBoxIcon.Information);
return false;
}
finally
{
if (connection.State == ConnectionState.Open)
{
connection.Close();
}
}
return true;
}
return false;
}
My GrantAccess function to allow permission for current app
public static bool GrantAccess(string fullPath)
{
DirectoryInfo info = new DirectoryInfo(fullPath);
WindowsIdentity self = System.Security.Principal.WindowsIdentity.GetCurrent();
DirectorySecurity ds = info.GetAccessControl();
ds.AddAccessRule(new FileSystemAccessRule(self.Name,
FileSystemRights.FullControl,
InheritanceFlags.ObjectInherit |
InheritanceFlags.ContainerInherit,
PropagationFlags.None,
AccessControlType.Allow));
info.SetAccessControl(ds);
return true;
}
Check Database exists function below
public static bool CheckDatabaseExists(SqlConnection tmpConn, string databaseName)
{
string sqlCreateDBQuery;
bool result = false;
try
{
sqlCreateDBQuery = string.Format("SELECT database_id FROM sys.databases WHERE Name = '{0}'", databaseName);
using (SqlCommand sqlCmd = new SqlCommand(sqlCreateDBQuery, tmpConn))
{
tmpConn.Open();
object resultObj = sqlCmd.ExecuteScalar();
int databaseID = 0;
if (resultObj != null)
{
int.TryParse(resultObj.ToString(), out databaseID);
}
tmpConn.Close();
result = (databaseID > 0);
}
}
catch (Exception)
{
result = false;
}
return result;
}

Based on this support article https://support.microsoft.com/en-us/kb/307283 which has a similar database creation script I suggest removing the "CONTAINMENT = NONE" section.
By default, all SQL Server 2012 and later databases have a containment set to NONE.(https://msdn.microsoft.com/en-us/library/ff929071.aspx), so it probably isn't necessary for your script
It is possible that ado .net doesn't support that tsql command, there is a whole other SQL Server Management Objects library available for messing with advance database and schema scripts https://msdn.microsoft.com/en-us/library/ms162169.aspx . I've used it to create missing databases with table definitions etc during application startup.

To simplify things, here is an even shorter solution.
public void CreateDatabaseIfNotExists(string connectionString, string dbName)
{
SqlCommand cmd = null;
using (var connection = new SqlConnection(connectionString))
{
connection.Open();
using (cmd = new SqlCommand($"If(db_id(N'{dbName}') IS NULL) CREATE DATABASE [{dbName}]", connection))
{
cmd.ExecuteNonQuery();
}
}
}

C# how to check if database is not busy?

My class has a couple of methods going on. The first one is creating a database, that's done. Then, creates stored procedures that is being read from a sql file. then detach that DB. Now it seems that my store procedure query is taking a while to finish and my method to detach is being invoked while the database is busy. So how do I tell if the database is idle. The exception goes "cannot detach the database because it is currently in use"
Methods:
void CreateStoredProcedures(string type)
{
string spLocation = File.ReadAllText("CreateStoredProcedures.sql");
var conn = new SqlConnection(connectionString + ";database=" + type + DateTime.Now.ToString("yyyyMMdd"));
try
{
Server server = new Server(new ServerConnection(conn));
server.ConnectionContext.ExecuteNonQuery(spLocation);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
bool DetachBackup(string type)
{
var conn = new SqlConnection(connectionString);
SqlCommand command = new SqlCommand("", conn);
command.CommandText = #"sys.sp_detach_db '" + type + DateTime.Now.ToString("yyyyMMdd") + "'";
try
{
conn.Open();
command.ExecuteNonQuery();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
return false;
}
finally
{
if ((conn.State == ConnectionState.Open))
{
conn.Close();
}
}
return true;
}
Click event:
private void btnFullBackup_Click(object sender, EventArgs e)
{
lblStatus.Text = "Starting full backup...";
Execute("FULL");
progressBar.Value = 20;
lblStatus.Text = "Copying tables...";
progressBar.Value = 60;
CopyTables("FULL");
progressBar.Value = 70;
lblStatus.Text = "Creating stored procedures...";
CreateStoredProcedures("FULL");
progressBar.Value = 80;
CheckDBSize(newBackupLocation, "FULL");
progressBar.Value = 100;
MessageBox.Show("Backup was created successfully", "",
MessageBoxButtons.OK, MessageBoxIcon.Information);
lblStatus.Text = "Done";
progressBar.Value = 0;
if (DetachBackup("FULL") == false)
{
DetachBackup("FULL");
}
}

Chances are it's getting hung on its own connection. sp_detach_db's MSDN https://msdn.microsoft.com/en-CA/library/ms188031.aspx has the following suggestion under the section Obtain Exclusive Access:
USE master;
ALTER DATABASE [DBName] SET SINGLE_USER;
You're DetachBackup method will have connect to master, run the ALTER and the sp_detach_db procedure.

You aren't closing the connection in your CreateStoredProcedures method. Put using statements in like I've shown here and it should fix the problem. (Brief using statement explanation from Microsoft.)
Try this code for your methods:
void CreateStoredProcedures(string type)
{
string spLocation = File.ReadAllText("CreateStoredProcedures.sql");
using (var conn = new SqlConnection(connectionString + ";database=" + type + DateTime.Now.ToString("yyyyMMdd")))
{
try
{
Server server = new Server(new ServerConnection(conn));
server.ConnectionContext.ExecuteNonQuery(spLocation);
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
} // End of using, connection will always close when you reach this point.
}
bool DetachBackup(string type)
{
using (var conn = new SqlConnection(connectionString))
{
SqlCommand command = new SqlCommand(#"sys.sp_detach_db '" + type + DateTime.Now.ToString("yyyyMMdd") + "'", conn);
try
{
conn.Open();
command.ExecuteNonQuery();
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
return false;
}
} // End of using, connection will always close when you reach this point.
return true;
}

You shouldn't think of it as the database being "busy", but the error message uses good verbage: in use. To find out if the database is currently in use, the most accurate way would be to find out if any sessions have any lock in the particular database, by querying sys.dm_tran_locks. Here is a helper function to return a bool whether or not the database is in use:
bool IsDatabaseInUse(string databaseName)
{
using (SqlConnection sqlConnection = new SqlConnection("... your connection string ..."))
using (SqlCommand sqlCmd = new SqlCommand())
{
sqlCmd.Connection = sqlConnection;
sqlCmd.CommandText =
#"select count(*)
from sys.dm_tran_locks
where resource_database_id = db_id(#database_name);";
sqlCmd.Parameters.Add(new SqlParameter("#database_name", SqlDbType.NVarChar, 128)
{
Value = databaseName
});
sqlConnection.Open();
int sessionCount = Convert.ToInt32(sqlCmd.ExecuteScalar());
if (sessionCount > 0)
return true;
else
return false;
}
}
Note: Make sure your initial catalog in your connection string isn't the database you're trying to make "not in use", as that'll put your current session in the context of the database, not allowing that operation to complete

Issues with mysql in c#

I have a small problem with connecting c# with a mysql database. When im trying to insert a value from a textbox i get the error below. I was wondering if someone could help me/ explain to me what im doeing wrong.
This is the error that i'm getting:
Unknown column 'test' in 'field list'
This is my code for connecting to the database:
namespace Planner
{
internal class DBConnect
{
private MySqlConnection _connection = new MySqlConnection();
private string _server;
private string _database;
private string _uid;
private string _password;
//private string _port;
//private bool succes = false;
//Constructor
public DBConnect()
{
Initialize();
}
//Initialize values
public void Initialize()
{
string connectionString2 = "Server=localhost;Port=3307;Database=test;Uid=root;Pwd=usbw";
//+ "Port:" + _port + ";"
_server = "localhost:3307";
//_port = "3307";
_database = "test";
_uid = "root";
_password = "usbw";
string connectionString = "Server=" + _server + ";" + "Database=" +
_database + ";" + "Uid=" + _uid + ";" + "Pwd=" + _password + ";";
_connection = new MySqlConnection(connectionString2);
}
public bool OpenConnection()
{
try
{
_connection.Open();
return true;
}
catch (MySqlException ex)
{
switch (ex.Number)
{
case 0:
MessageBox.Show("Cannot connect to server");
break;
case 1042:
MessageBox.Show("Unable to connect to any of the specified MySQL hosts");
break;
case 1045:
MessageBox.Show("Invalid username/password");
break;
}
return false;
}
}
private List<string>[] Select()
{
string selectquery = "SELECT * FROM tabelname";
List<string>[] selectlist = new List<string>[3];
selectlist[0] = new List<string>();
selectlist[1] = new List<string>();
selectlist[2] = new List<string>();
MySqlCommand cmd = new MySqlCommand(selectquery, _connection);
MySqlDataReader dataReader = cmd.ExecuteReader();
while (dataReader.Read())
{
selectlist[0].Add(dataReader["waarde"] + "");
selectlist[1].Add(dataReader["waarde"] + "");
selectlist[2].Add(dataReader["waarde"] + "");
}
dataReader.Close();
return selectlist;
}
public void Insert(string textvalue)
{
string insertquery = "INSERT INTO testconnectie(text) VALUES ("+textvalue+")";
MySqlCommand cmd = new MySqlCommand(insertquery, _connection);
cmd.ExecuteNonQuery();
}
private void Update()
{
string updatequery = "UPDATE tabelnaam SET waarde='', waarde'' WHERE waarde=''";
MySqlCommand cmd = new MySqlCommand();
cmd.CommandText = updatequery;
cmd.Connection = _connection;
cmd.ExecuteNonQuery();
}
private void Delete()
{
string deletequery = "DELETE FROM tabelnaam WHERE waarde=''";
MySqlCommand cmd = new MySqlCommand(deletequery, _connection);
cmd.ExecuteNonQuery();
}
public bool CloseConnection()
{
try
{
_connection.Close();
return true;
}
catch (MySqlException ex)
{
MessageBox.Show(ex.Message);
return false;
}
}
public void Backup()
{
try
{
DateTime Time = DateTime.Now;
int year = Time.Year;
int month = Time.Month;
int day = Time.Day;
int hour = Time.Hour;
int minute = Time.Minute;
int second = Time.Second;
int millisecond = Time.Millisecond;
//Save file to C:\ with the current date as a filename
string path;
path = "C:\\ChatBackup" + year + "-" + month + "-" + day +
"-" + hour + "-" + minute + "-" + second + "-" + millisecond + ".sql";
StreamWriter file = new StreamWriter(path);
ProcessStartInfo psi = new ProcessStartInfo();
psi.FileName = "Database Backup";
psi.RedirectStandardInput = false;
psi.RedirectStandardOutput = true;
psi.Arguments = string.Format(#"-u{0} -p{1} -h{2} {3}",
_uid, _password, _server, _database);
psi.UseShellExecute = false;
Process process = Process.Start(psi);
string output;
output = process.StandardOutput.ReadToEnd();
file.WriteLine(output);
process.WaitForExit();
file.Close();
process.Close();
}
catch (IOException ex)
{
MessageBox.Show("Error , unable to backup! " + ex);
}
}
}
}
Mainform
namespace Planner
{
public partial class MainForm : Form
{
private DBConnect mysql = new DBConnect();
public MainForm()
{
InitializeComponent();
mysql.Initialize();
mysql.OpenConnection();
}
private void _sendMessageButton_Click(object sender, System.EventArgs e)
{
string textvalue = _messageTextBox.Text;
mysql.Insert(textvalue);
}
}
}
Can someone explain to my what im doeing wrong, thanks in advance.

you miss single quote, use like this
string insertquery = "INSERT INTO testconnectie(text) VALUES ('"+textvalue+"')";

use parameters: it is safe and you can avoid most of the exceptions like you currently get
string insertquery = "INSERT INTO YourTableName ([yourColumnName]) VALUES (#ParameterName)";
using (var con = new MySqlConnection(connectionString))
using (var cmd = new MySqlCommand(insertquery, con))
{
cmd.Parameters.AddWithValue("#ParameterName", textvalue);
con.Open();
cmd.ExecuteNonQuery();
}

C# Connect to a SQL server CE programmatically

I'm completely new to database programming. I'm working with Visual Studio 2010 and want to create a database programmatically.
So far I've tried to connect to a SQL Server Compact Edition like this:
public class HistoryDBAccess
{
private SqlConnection conn = new SqlConnection();
public HistoryDBAccess()
{
conn.ConnectionString = #"Server=localhost;Integrated security=SSPI;database=master";
string str = "CREATE DATABASE MyDatabase ON PRIMARY " +
"(NAME = MyDatabase_Data, " +
"FILENAME = 'C:\\MyDatabaseData.mdf', " +
"SIZE = 2MB, MAXSIZE = 10MB, FILEGROWTH = 10%) " +
"LOG ON (NAME = MyDatabase_Log, " +
"FILENAME = 'C:\\MyDatabaseLog.ldf', " +
"SIZE = 1MB, " +
"MAXSIZE = 5MB, " +
"FILEGROWTH = 10%)";
SqlCommand myCommand = new SqlCommand(str, conn);
try
{
conn.Open();
myCommand.ExecuteNonQuery();
MessageBox.Show("DataBase is Created Successfully", "MyProgram", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
catch (System.Exception ex)
{
MessageBox.Show(ex.ToString(), "MyProgram", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
finally
{
if (conn.State == System.Data.ConnectionState.Open)
{
conn.Close();
}
}
}
}
The connection in the Ctor fails with the message that a connection could not be established.
Using the database wizard with VS2010 is fine, but how I can see the SQLCe server under windows 7?
Is it somewhere under the control panel and do I need a default password in the connection string?
Many thanks,
Juergen

I think you should add a connection to your database in Your project using Server Explorer(or Database Explorer) Then check your Connection string.

It looks like you are trying to pass the con object before opening the connection.
So Try this and let me know.
public HistoryDBAccess()
{
conn.ConnectionString = #"Server=localhost;Integrated security=SSPI;database=master";
string str = "CREATE DATABASE MyDatabase ON PRIMARY " +
"(NAME = MyDatabase_Data, " +
"FILENAME = 'C:\\MyDatabaseData.mdf', " +
"SIZE = 2MB, MAXSIZE = 10MB, FILEGROWTH = 10%) " +
"LOG ON (NAME = MyDatabase_Log, " +
"FILENAME = 'C:\\MyDatabaseLog.ldf', " +
"SIZE = 1MB, " +
"MAXSIZE = 5MB, " +
"FILEGROWTH = 10%)";
conn.Open();
SqlCommand myCommand = new SqlCommand(str, conn);
try
{
myCommand.ExecuteNonQuery();
MessageBox.Show("DataBase is Created Successfully", "MyProgram", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
catch (System.Exception ex)
{
MessageBox.Show(ex.ToString(), "MyProgram", MessageBoxButtons.OK, MessageBoxIcon.Information);
}
finally
{
if (conn.State == System.Data.ConnectionState.Open)
{
conn.Close();
}
}
}
}

Once you create it, you're probably going to want to interact with it. You should consider using NHibernate. It has a feature called SchemaExport that can drop and create databases as much as you like.
Here's an example using SQL Express, but it's not much different to use Compact Edition. You can get NHibernate installed in your project by opening it in Visual Studio and clicking Project > Manage NuGet Packages, then searching All Online for NHibernate.
public class NHContext
{
protected static Configuration NHConfiguration;
protected static ISessionFactory SessionFactory;
public static void DropDatabase()
{
new SchemaExport(NHConfiguration).Drop(false, true);
}
public static void CreateDatabase()
{
new SchemaExport(NHConfiguration).Create(false, true);
}
protected static Configuration configureNHibernate()
{
var configure = new Configuration();
configure.SessionFactoryName("BuildIt");
configure.DataBaseIntegration(db =>
{
db.Dialect<MsSql2008Dialect>();
db.Driver<Sql2008ClientDriver>();//db.Driver<SqlClientDriver>();
db.KeywordsAutoImport = Hbm2DDLKeyWords.AutoQuote;
db.IsolationLevel = IsolationLevel.ReadCommitted;
db.ConnectionString = #"Data Source=.\SQLEXPRESS;Persist Security Info=True;Integrated Security=SSPI;Initial Catalog=NHibernate32Test;User Instance=False";
db.Timeout = 10;
// For testing
db.LogFormattedSql = true;
db.LogSqlInConsole = true;
db.AutoCommentSql = true;
});
return configure;
}
public static void Setup()
{
NHConfiguration = configureNHibernate();
HbmMapping mapping = getMappings();
NHConfiguration.AddDeserializedMapping(mapping, "NHibernate32Test");
SchemaMetadataUpdater.QuoteTableAndColumns(NHConfiguration);
SessionFactory = NHConfiguration.BuildSessionFactory();
}
}

Can't insert a record in a oracle database using C#

try
{
int val4 = Convert.ToInt32(tbGrupa.Text);
string MyConString = "Data Source=**;User ID=******;Password=*****";
OracleConnection conexiune = new OracleConnection(MyConString);
OracleCommand comanda = new OracleCommand();
comanda.Connection = conexiune;
conexiune.Open();
comanda.Transaction = conexiune.BeginTransaction();
int id_stud = Convert.ToInt16(tbCodStud.Text);
string nume = tbNume.Text;
string prenume = tbPrenume.Text;
string initiala_tatalui = tbInitiala.Text;
string email = tbEmail.Text;
string facultate = tbFac.Text;
int grupa = Convert.ToInt16(tbGrupa.Text);
string serie = tbSeria.Text;
string forma_de_inv = tbFormaInvatamant.Text;
DateTime data_acceptare_coordonare = dateTimePicker1.Value;
DateTime data_sustinere_licenta = dateTimePicker2.Value;
string sustinere = tbSustinereLicenta.Text;
string parola_acces = tbParola.Text;
try
{
comanda.Parameters.AddWithValue("id_stud", id_stud);
comanda.Parameters.AddWithValue("nume", nume);
comanda.Parameters.AddWithValue("prenume", prenume);
comanda.Parameters.AddWithValue("initiala_tatalui", initiala_tatalui);
comanda.Parameters.AddWithValue("facultate", facultate);
comanda.Parameters.AddWithValue("email", email);
comanda.Parameters.AddWithValue("seria", serie);
comanda.Parameters.AddWithValue("grupa", grupa);
comanda.Parameters.AddWithValue("forma_de_inv", forma_de_inv);
comanda.Parameters.AddWithValue("data_acceptare_coordonare", data_acceptare_coordonare);
comanda.Parameters.AddWithValue("data_sustinere_licenta", data_sustinere_licenta);
comanda.Parameters.AddWithValue("sustinere_licenta", sustinere);
comanda.Parameters.AddWithValue("parola_acces", parola_acces);
comanda.Transaction.Commit();
MessageBox.Show("Studentul " + tbNume.Text + " " + tbPrenume.Text + " a fost adăugat în baza de date!");
}
catch (Exception er)
{
comanda.Transaction.Rollback();
MessageBox.Show("ER1.1:" + er.Message);
MessageBox.Show("ER1.2:" + er.StackTrace);
}
finally
{
conexiune.Close();
}
}
catch (Exception ex)
{
MessageBox.Show("ER2.1:"+ex.Message);
MessageBox.Show("ER2.2:"+ex.StackTrace);
}

There doesn't seem to be an insert statement. I think this is what the problem is. You would need some thing like:
using (OracleConnection connection = new OracleConnection(connectionString))
{
OracleCommand command = new OracleCommand(myExecuteQuery, connection);
command.Connection.Open();
command.ExecuteNonQuery();
}
There's a commit statement, what what are you going to commit if there's no insert statement prior to that?